Fibromyalgia (FM) and Major Depressive Disorder (MDD) are chronic, costly, debilitating diseases that have co-occurring symptoms including generalized pain, neuroendocrine disturbances, and hypothalamic-pituitary- adrenal (HPA) axis perturbations. The purpose of the proposed study is to directly test the hypothesis that depression subtypes exist in FM and can be identified via chemical assays and clinical characteristics. 27 subjects per group will be recruited: FM without concurrent depression (FM no MDD), FM with Atypical Depressive Episodes (FM/ADE), and FM with Melanacholic Depressive Episodes (FM/MDE). Aim 1 is to describe the clinical characteristics of subjects with FM/MDE, FM/ADE and FM no depression. It is hypothesized there will be significant differences between the 3 groups on measures of FM and depression severity, sleep quality, quality of life and body mass index. Aim 2 is to determine whether there are significant differences in suppression of the HPA axis, as evidenced by plasma cortisol levels, between FM/MDE, FM/ADE, and FM no MDD groups. It is hypothesized the FM/MDE group will have impaired HPA suppression, as evidenced by higher cortisol levels, compared to FM/ADE and FM no depression groups. Aim 3 is to determine whether there are differences in the serum IGF-I levels between FM/MDE groups compared to FM/ADE and FM no depression. It is hypothesized the FM/MDE group will have lower IGF-I levels than FM/ADE and FM no depression groups.